Where is the A/C expansion valve on the W210?
 

Any tips on accessing and replacing it? Thanks!

Left side under hood under cowling, not a bad job, but, you may not want to tackle it yourself if you dont how the pieces come apart to access everything.

OK. Thanks.

BTW Cudaspaz, Are you a tech in the Atlanta area? Where do you work?

Bump - does anybody have a pic or diagram of the A/C cowling removed to access the TXV? Does the wiper transmission have to come off?

I've done 2 in the past week
 

First recover what's left of the refrigerant. Remove cowl panels on each side of wiper assembly. Remove wiper assembly. Remove large cowl paneling under wiper assembly. Unscrew 10mm nut to remove lines to expansion valve. Unscrew two allen bolts going through expansion valve(these are very small allens, like a 3 maybe. Remove expansion valve and replace all 4 orings. Replace the reciever drier and all o rings. Check to make sure the lines going to the expansion valve are not leaking as these commonly do. I hope this helps. The job should take you a few hours.
Dustin

Very helpful - I should be trying this within the next week or so. How difficult is the removal of the wiper assembly?

It's a very easy job in my opinion, but I have done it a few times. When you pop the hood, on each side of the cowling you'll see a screw. Remove the screw. The cowling then slides towards the center of the car. Remove each side( one piece of cowling on each side of the wiper). Next you'll see 4 screws on the driver's side and a push pin, and 3 screws on the pass. side and a push pin(white plastic pin). Remove all of this hardware. Now you can unsnap the cowling from the front (towards the engine) and remove. There is a plastic trim panel under the wiper assembly in the center that slides out as well. Now remove the 3 10mm nuts(2 nuts and one bolt) which secures the wiper assembly. Unclip the wiper assembly from the white plastic clip in the front. Unplug the wiper and remove. Once you have removed the wiper, remove the large wiper mounts with a pair of pliers or if you have a socket large enough.(they are not that tight). Now, with a little pulling and tweaking you can remove the large cowling which sits underneath the wiper. You can also choose to leave this in if you wish, but you have more room if you remove it. Also if you choose to remove it you will have to remove that white plastic piece that the wiper clips to. I think it takes a 5 allen? Remove the 10mm nut that holds the lines to the expansion valve...

the nice thing about that setup..is that the evaporator is right there and can be replaced as well....

It's right there if you remove the dashboard.

quite a few years ago...when i was trying to decide on a 190 or 300, i saw a write up with pictures.. it showed someone accessing and replacing the evaporator from the engine bay..

i don't think i am that senile yet... could be though.

Funny, my expansion valve seems to be stuck wide open, at least from what I have read about its symptoms. With the system fully charged I still hear the telltale hissing that usually accompanies low refrigerant. The car cools OK, though not quite as fast when you first start it up after it has sat in the hot sun. It also cools much better at idle than at speed, ironically.

Had I known the valve was suspect last fall when I replaced my condensor and receiver-drier I'd have done it then, but since I have a fresh charge of R134a in there I will just wait until next time it leaks out or if it gets worse I'll deal with it then, but thanks for the write up...I'll keep it in my files for that day I need it.

And no, my understanding is the evaporator only comes out the inside of the car not from under the hood...I thought I had a leak in mine but it turned out to be the condensor which is a snap to replace by comparison...dodged that bullet!

The 190 has the evap which is easily accessible. But that is a 201. We are talking about a 210 (successor to the W124).

transposed those numbers.. 201 210...sorry.